1. “AIM membership directory.” (1986). Automatic Identification Manufacturers Pittsburgh Pa.
2. Allias D. C. (1985). Bar code symbology: Some observations on theory and practice . Intermec Corp. Lynwood Wash.
3. “Automatic ID educational material directory.” (1987). Automatic Identification Manufacturers Pittsburgh Pa.
4. “Bar Code Symbology Standard.” (1984). Automotive Industry Action Group Southfield Mich.
5. Burke H. E. (1984). Handbook of bar coding systems . Van Nostrand Reinhold Company New York N.Y.